Analysis on Risk Characteristics of Traffic Accidents in Small-Spacing Expressway Interchange

Area of Science:

• Traffic Engineering
• Road Safety Analysis
• Transportation Systems

Background:

• Increasing expressway interchange density leads to more small-spacing interchanges (SSI).
• The specific traffic accident characteristics within SSI remain unclear.
• Understanding SSI safety is crucial for effective traffic management.

Purpose of the Study:

• To systematically explore and explain the accident characteristics of small-spacing interchanges (SSI).
• To identify factors influencing expressway traffic safety, particularly in areas with SSI.
• To provide a theoretical basis for accident prevention in SSI.

Main Methods:

• Dividing the G3001 expressway into four sections for analysis.
• Evaluating safety using the number of accidents per unit distance of 100 million vehicles (NAP).
• Employing statistical analysis, least square support vector machine (LSSVM), random forest, and logistic regression models with multiple indicators (e.g., mean spacing distance, traffic volume, road conditions).

Main Results:

• Sections I and II with SSI exhibited higher NAP values (27.2 and 33.7, respectively).
• Key factors adversely affecting expressway safety include interchange density, annual average daily traffic, and mean spacing distance (MSD).
• Road conditions were identified as the primary influence on serious traffic accidents within SSI.

Conclusions:

• SSI are associated with elevated accident rates compared to normal-spacing interchanges (NSI).
• Traffic density and interchange spacing are critical determinants of expressway safety.
• Targeted interventions focusing on road conditions are essential for mitigating serious accidents in SSI zones.